The 41Ca bomb pulse and atmospheric transport of radionuclides

For the first time, the 41Ca signal from the nuclear weapon tests has been measured. Calcium 41 concentrations have been determined in alpine ice of the Fiescherhorn glacier (Switzerland) with accelerator mass spectrometry. The peak concentrations have been observed to be about 3×106 atoms of 41Ca p...

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Bibliographic Details
Published in:Journal of Geophysical Research: Atmospheres 1997-08, Vol.102 (D16), p.19517-19527
Main Authors: Zerle, L., Faestermann, T., Knie, K., Korschinek, G., Nolte, E., Beer, J., Schotterer, U.
Format: Article
Language:English
Subjects:
Chemical composition and interactions. Ionic interactions and processes
Earth, ocean, space
Exact sciences and technology
External geophysics
Meteorology
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Summary:For the first time, the 41Ca signal from the nuclear weapon tests has been measured. Calcium 41 concentrations have been determined in alpine ice of the Fiescherhorn glacier (Switzerland) with accelerator mass spectrometry. The peak concentrations have been observed to be about 3×106 atoms of 41Ca per kilogram of ice in. the 1950s. It has been found that 41Ca is produced essentially by the atoll bombs. A universal box model, able to describe atmospheric transport of radionuclides that are in gaseous form or attached to aerosols, has been developed. The model has been applied to calculate the bomb pulses of 14C, 36Cl, 41Ca, 90Sr, and 137Cs, For the transport of radionuclides that are attached to aerosols such as 41Ca, 90Sr, and 137Cs, sedimentation (gravitational settling) in the upper stratosphere has been taken into account. It has been found that the deposition of bomb‐produced 36Cl on the Earth's surface is delayed compared to that of 90Sr by about 1 year because 36Cl stays gaseous in the stratosphere. The model can also be used to calculate the deposition of cosmogenic radionuclides, e.g., 36Cl and 10Be, in their natural archives, such as polar ice sheets.
ISSN:0148-0227
2156-2202
DOI:10.1029/97JD00701